Correction: Magnetic mesoporous silica/ε-polylysine nanomotor-based removers of blood Pb2+

Correction for ‘Magnetic mesoporous silica/ε-polylysine nanomotor-based removers of blood Pb2+’ by Zhiyong Liu et al., J. Mater. Chem. B, 2020, 8, 11055–11062, DOI: 10.1039/D0TB02270E.

Yolk–shell structured magnetic mesoporous silica: a novel and highly efficient adsorbent for removal of methylene blue

In this study, a novel magnetic mesoporous silica with yolk–shell structure (Fe3O4@[email protected]) was successfully synthesized via a polymer-template assisted method. The Fe3O4@[email protected] was characterized by using FT-IR, EDS, SEM, TEM, VSM, PXRD and nitrogen adsorption–desorption analyses. The Fe3O4@[email protected] nanocomposite showed high efficiency in adsorption of an organic dye and water pollutant called methylene blue (MB) with 98.2% removal capability. Furthermore, the effect of different parameters in the adsorption of MB was investigated. Different models of kinetic were examined and compared with each other. The recoverability and reusability of designed Fe3O4@[email protected] material were also studied under applied conditions.

Improving anti-cancer drug delivery performance of magnetic mesoporous silica nanocarriers for more efficient colorectal cancer therapy

Background Improving anti-cancer drug delivery performance can be achieved through designing smart and targeted drug delivery systems (DDSs). For this aim, it is important to evaluate overexpressed biomarkers in the tumor microenvironment (TME) for optimizing DDSs. Materials and methods Herein, we designed a novel DDS based on magnetic mesoporous silica core–shell nanoparticles (SPION@MSNs) in which release of doxorubicin (DOX) at the physiologic pH was blocked with gold gatekeepers. In this platform, we conjugated heterofunctional polyethylene glycol (PEG) onto the outer surface of nanocarriers to increase their biocompatibility. At the final stage, an epithelial cell adhesion molecule (EpCAM) aptamer as an active targeting moiety was covalently attached (Apt-PEG-Au@NPs-DOX) for selective drug delivery to colorectal cancer (CRC) cells. The physicochemical properties of non-targeted and targeted nanocarriers were fully characterized. The anti-cancer activity, cellular internalization, and then the cell death mechanism of prepared nanocarriers were determined and compared in vitro. Finally, tumor inhibitory effects, biodistribution and possible side effects of the nanocarriers were evaluated in immunocompromised C57BL/6 mice bearing human HT-29 tumors. Results Nanocarriers were successfully synthesized with a mean final size diameter of 58.22 ± 8.54 nm. Higher cytotoxicity and cellular uptake of targeted nanocarriers were shown in the EpCAM-positive HT-29 cells as compared to the EpCAM-negative CHO cells, indicating the efficacy of aptamer as a targeting agent. In vivo results in a humanized mouse model showed that targeted nanocarriers could effectively increase DOX accumulation in the tumor site, inhibit tumor growth, and reduce the adverse side effects. Conclusion These results suggest that corporation of a magnetic core, gold gatekeeper, PEG and aptamer can strongly improve drug delivery performance and provide a theranostic DDS for efficient CRC therapy. Graphic abstract

4-Nitrophenol-Loaded Magnetic Mesoporous Silica Hybrid Materials for Spectrometric Aptasensing of Carcinoembryonic Antigen

Aptamer- or antibody-based sensing protocols have been reported for detecting carcinoembryonic antigen (CEA), but most exhibit complicated procedures or multiple reactions. In this work, we developed a one-step aptasensing protocol for the spectrometric determination of CEA based on 4-nitrophenol (4-NP)-loaded magnetic mesoporous silica nanohybrids (MMSNs) for bioresponsive controlled-release applications. To fabricate such a responsive–controlled sensing system, single-stranded complementary oligonucleotides relative to the CEA-specific aptamer were first modified on the aminated MMSN. Thereafter, 4-NP molecules blocked the pores with the assistance of the aptamers via a hybridization reaction. The introduced target CEA specifically reacted with the hybridized aptamer, thus detaching from the MMSN to open the gate. The loaded 4-NP molecules were released from the pores, as determined using ultraviolet–visible (UV–vis) absorption spectroscopy after magnetic separation. Under optimum conditions, the absorbance increased with an increase in the target CEA in the sample and exhibited a good linear relationship within the dynamic range of 0.1–100 ng mL−1, with a detection limit of 46 pg mL−1. Moreover, this system also displayed high specificity, good reproducibility, and acceptable accuracy for analyzing human serum specimens, in comparison with a commercialized human CEA-enzyme-linked immunosorbent assay (ELISA) kit.

Magnetic Mesoporous Silica Nanoparticles Incorporated with miR-451 Suppress Development of Cervical Cancer and Enhance Radio Sensitization in Cervical Cancer

Cervical cancer (CC) is one of the most common gynecological malignancies with high mortality, threatening female’s health and reducing their life quality. This study evaluated the synergistic effect of magnetic mesoporous silica nanoparticles (MMSNs), miR-451 on radio sensitivity and cell apoptosis in CC. Magnetic mesoporous silica (Fe3O4/SiO2) nanoparticles were prepared and loaded with miR-451. Then the CC cells were treated with Fe3O4/SiO2 nanoparticles, miR-451-loaded Fe3O4/SiO2 nanoparticles (control group) and untreated (blank group). Cell proliferation was determined by MTT assay, while apoptosis and Hoechst were assessed by flow cytometry. As colony formation assay was conducted to evaluate cell sensitivity to radiotherapy, Western blot analysis detected the expression of apoptosis- and radiosensitization-related genes. Iron oxide particles were present inside and outside the SiO2 channel with characteristic peaks for Fe and skeleton of silica. The miR-451-loaded Fe3O4/SiO2 nanoparticles had an obvious absorption peak with drug loading rate and encapsulation rate reaching 6% and 91%. The release content of drugs increased with decreased pH. Of note, combined treatment with miR-451 and Fe3O4/SiO2 nanoparticles significantly decreased cancer cell proliferation and increased apoptosis (34.36±2.31%), compared to control group and blank group. Furthermore, the levels of D0 (1.67), Dq (0.94), N (1.56), and SF2 (0.43) declined in the presence of miR-451-Fe3O4/SiO2 nanoparticles, accompanied with elevation of ATM and γ-H2AX expression. Meanwhile, the treated CC cells had decreased expressions of DNA damage repair related genes ATM and γ-H2AX. MMSNs carrying miR-451 decreased cell proliferation activity and increased apoptosis and sensitized the CC cells to radiotherapy, to improve tissue repairing. These findings may provide a novel insight into pathogenesis of CC.

Galactosylated Chitosan Modified Magnetic Mesoporous Silica Nanoparticles Loaded with Nedaplatin for the Targeted Chemo-Photothermal Synergistic Therapy of Cancer

The use of chemotherapy combined with photothermal therapy (PTT) is getting a focus topic for cancer treatment. Duing this research, the double targeting drug delivery system of nedaplatin (NDP)–carboxyl-functionalized magnetic mesoporous silica (MMSN-COOH)–galactosylated chitosan (GC) nanoparticles (NPs) was constructed. Because MMSNs have special physical properties, it can target to the specific area. In addition, it’s able to convert absorbed near-infrared (NIR) light into heat energy for photothermal therapy (PTT). Furthermore, the thermal energy generated by MMSNs under NIR lasers can accelerate the release of drug from preparations. Moreover, GC modified MMSNs-COOH as a carrier can increase the drug uptake of cancer cells that highly express galectins in vitro, resulting in cancer cell apoptosis, and thus increasing the targeting of cancerous tissue in vivo. The experimental consequences in vitro and in vivo revealed that the NDP@MMSNCOOH-GC NPs combined with PTT could avoid systemic toxicity and improve biosecurity while having good anticancer effect.